1. Field of the Invention
The present invention relates to novel cleaning/stripping compositions based on sulfamic acid and incorporating a heteropolysaccharide of succinoglycan type as a thickening agent therefor.
2. Description of the Prior Art
It is conventional in this art to employ compositions for treating surfaces which are covered or coated with inorganic and/or organic contaminating deposits. These inorganic deposits generally are compounds such as carbonates, sulfates and oxides of metals, for example of calcium, magnesium, potassium and iron. The acid included in these compositions is generally selected on the basis of the chemical nature of the deposit to be removed. Among the most frequently used such acids, particularly exemplary thereof are phosphoric acid, which is more specific for stripping rust, hydrochloric and formic acids, which are appropriate for descaling porcelain surfaces, and sulfamic acid. Among the aforesaid acids, sulfamic acid proves to be very effective. However, its strong acidity, which is an advantage in terms of efficacy, presents a serious problem in respect of the preparation of corresponding formulations therefrom.
Indeed, the known stripping compositions typically incorporate a viscosity modifying agent which is intended to render them less fluid. There then follows a prolonged period of time of contact between the acid and the surface to be cleaned, which is thus beneficial to the activity of the acid with respect to the substrate or surface to which it is applied. Xanthan gum proves to be one of the most typically employed viscosity modifying agents and numerous cleaning compositions comprised thereof are known to this art, for example those described in EP-233,110.
Nonetheless, in contradistinction to the other acids indicated above, sulfamic acid is incompatible with xanthan gum taking account of its low pK, on the order of 1. Thus, the xanthan gum is degraded rapidly when contacted with sulfamic acid. Hence, thickened formulations based on sulfamic acid and having viscosities which are stable over time are not currently available.